The present invention relates to a control apparatus for an actuator, and, more particularly, to a control apparatus for an actuator which is operated by controlling fluid compression.
In accordance with one known type of actuator which is operated by compressing fluid, there consists, for example, a single acting type fluid pressure cylinder wherein fluid pressure acts on one side of a piston and wherein the piston is returned by its own weight or a load or spring force. An example of means to control the feed of the fluid pressure with respect to the single acting type fluid pressure cylinder employs a three-way valve as described in the publication `Fluid Power Control` published in the U.S. in 1960, pp. 527-540. Regarding this, in a case where an actuator that is provided with an actuator driver having a long rise time or dead time is driven by a pulse width modulated control system, for example, in a case where an actuator such as single acting type air cylinder is driven according to the pulse width modulation control by an actuator driver such as proportional valve or solenoid valve, the period of a carrier wave must be several times longer than the response of the actuator driver. This has led to the problem where the responsiveness of the actuator to an input signal worsens drastically.